Testing the suitability of the Nepal-Somers stand table projection method for Eucalyptus grandis plantations in South Africa

Abstract

This study presents an application of a stand table projection method for varying stand densities of Eucalyptus grandis in South Africa. The projections of diameter at breast height (dbh) class frequencies are compatible with future values of basal area and stem number per hectare. The application requires an individual tree dbh growth function, a current stand table, and estimates of future basal area, and tree survival. The resulting stand table is adjusted by an algorithm that guarantees that the future stand table is compatible either with observed or predicted values of basal area and stem number per hectare. The results, based on a relatively small experimental dataset, are satisfactory. However, further work based on a larger dataset is required to evaluate the general suitability of the method for stand table projection of Eucalyptus grandis in South Africa, especially regarding variable site conditions. The particular contribution of this study is the fact that we were able to demonstrate the suitability of the Nepal and  Somers stand table projection method for a unique dataset from a very densitysensitive Correlated Curve Trend spacing trial. We also made an attempt to present a comprehensive example of a projection to facilitate practical application of this method in the KwaZulu-Natal coastal plain of South Africa.

Keywords: CCT experiments, dbh distribution, parameter recovery, stand table projection, Weibull distribution

Southern Forests 2009, 71(3): 207–214